1. Field of the Invention
The present invention relates to a silver halide photographic light-sensitive element having a dyed hydrophilic colloid layer.
2. Description of the Prior Art
In silver halide photographic light-sensitive elements, dyeing the photographic emulsion layers or other hydrophilic colloid layers so as to absorb light of a specific wavelength range has often been done.
When it is necessary to control the spectral composition of the light passing into the photographic emulsion layer, a dyed layer is generally provided at a position farther from the support than from the photographic emulsion layer. Such a dyed layer is called a filter layer. Where a plurality of photographic emulsion layers is present, the filter layer may be positioned between two of the layers.
Provision of a dyed layer, called an antihalation layer, between the photographic emulsion layer and the support or on the back of the support has been employed in order to inhibit blurring of images, that is, halation, caused by the phenomenon where light rays scattered after or during passage through the photographic emulsion layer are reflected at an interface between the emulsion layer and the support or at the surface of the support opposite to that upon which the emulsion layer is coated back into the photographic emulsion layer again. In cases where a plurality of photographic emulsion layers is present, the antihalation layer may be positioned between two of the emulsion layers.
In order to prevent a degradation of image sharpness caused by a scattering of light in the photographic emulsion layers (this phenomenon is generally called irradiation), dyeing of the photographic emulsion layers has been employed.
Usually water soluble dyes are added to those hydrophilic colloid layers which are to be dyed. These dyes must have the following characteristics.
(1) The dyes must have an appropriate spectral absorption corresponding to their use.
(2) The dyes must be photochemically inert. Namely, they must not have an adverse chemical influence upon the silver halide photographic emulsion layers, for example, decrease the sensitivity, degrade the latent image or cause fog to occur, etc.
(3) The dyes must be decolored during photographic processings or must be removed by dissolution into processing solutions or in water used for washing and a disadvantageous residual color must not remain on the photographic light-sensitive elements after processing.
Many attempts have been made by persons skilled in the art in order to find dyes which satisfy these requirements. For example, oxonol dyes such as the dyes described in British Pat. No. 506,385, U.S. Pat. Nos. 3,247,127, 2,533,472 and 3,379,533 and British Pat. No. 1,278,621, hemioxonol dyes such as the dyes described in British Pat. No. 584,609, styryl dyes such as the dyes described in U.S. Pat. No. 2,298,733, merocyanine dyes such as the dyes described in U.S. Pat. No. 2,493,747 and cyanine dyes such as the dyes described in U.S. Pat. No. 2,843,486 are known.
Many of the dyes which are to be decolored in the processing of the photographic emulsion layers are decolored by sulfites (or bisulfites) present in a development processing solution or by such salts under alkaline conditions, e.g., as described in, for example, British Pat. No. 506,385.
Where the dyed layer is a filter layer or is an antihalation layer positioned on the same side of the support as the photographic emulsion layer, it is often necessary for that layer only to be dyed selectively and other layers not to be substantially dyed. If this is not so, the dyed layer not only causes a disadvantageous spectral effect on the other layers but also the effect of this layer as a filter layer or an antihalation layer is deteriorated.
Many methods of dyeing selectively a specific hydrophilic colloid layer are known. However, the most commonly used method comprises incorporating a hydrophilic polymer having an opposite electric charge to the dye ion as a mordant in the hydrophilic colloid layer, by which the dyes is present only in that specific layer due to an interaction between the mordant and the dye molecule (which is based not only on adsorption by means of electric charges but also on formation of hydrophobic bonds). For instance, polymers derived from ethylenically unsaturated compounds having a dialkylaminoalkyl ester residue described in British Pat. No. 685,475, reaction products prepared by reacting polyvinyl alkyl ketone with aminoguanidine as described in British Pat. No. 850,281, and polymers derived from 2-methyl-1-vinylimidazole as described in U.S. Pat. No. 3,445,231 are known as mordants. Where a method of mordanting using such polymers is used, when the layer to which the dye was added is brought into contact with other hydrophilic colloid layers in a wet state, a portion of the dye sometimes diffuses from the former layer to the latter layer. The diffusion of the dye depends upon not only the chemical structure of the mordant but also on the chemical structure of the dye used.
Where the above described high molecular weight mordants are used, residual color on the light-sensitive elements easily occurs after photographic processings, and, particularly, after processing in which a shortened processing time is used. The reason for this is believed to be because the dye or reversible decolored products remain in the mordant containing layer and because the mordant still has a certain degree of bonding strength to the dye although the bonding strength of the mordant to the dye becomes fairly weak in alkaline solutions such as a developing solution. Such a difficulty also depends upon the chemical structure of the mordant and that of the dye.
Of the various water soluble dyes, merocyanine dyes having a benzoxazole nucleus as a basic nucleus and a pyrazolin-5-one nucleus as an acidic nucleus are known as dyes suitable for dyeing hydrophilic colloid layers of photographic light-sensitive materials since they are decolored in a developer solution containing sulfites and do not have any adverse influence upon the photographic properties of photographic emulsions. For example, the dyes described in U.S. Pat. No. 3,282,699 are known. However, the dyes described in U.S. Pat. No. 3,282,699 are not sufficiently mordanted and it is impossible to prevent a diffusion of the dyes into a layer which does not contain a mordant when a basic polymer having a specific structure is not used as a mordant, as described in U.S. Pat. No. 3,282,699.